Step-by-step placement of endovascular electroencephalography using the EP-01 system

Endovascular electroencephalography (eEEG) using the EP-01 electrode requires reliable venous access and secure fixation to maintain stable positioning. This technical note aims to describe a standardized workflow for EP-01 placement, focusing on preprocedural planning, step-by-step deployment, and fixation strategies.

We report 12 consecutive EP-01 placements performed between May 2024 and October 2025. Preprocedural planning utilized venous-phase angiography with three-dimensional reconstructions, as well as contrast-enhanced three-dimensional MRI when available, to assess venous anatomy and select appropriate access routes. Procedures were performed under general anesthesia using jugular venous sheaths and arterial angiographic guidance. EP-01 electrodes were deployed through microcatheters, and signal recordability was confirmed. Microcatheters were withdrawn using an extension wire to maintain electrode position. Electrodes were secured using Tuohy-Borst fixation and additional skin-level fixation with film dressing.

All 12 procedures were completed successfully (mean age 40.6±11.0 years; 4 women). The mean procedure time was 165.6±35.5 min and the mean fluoroscopy time was 51.8±9.4 min. Six electrodes were placed in 11 of 12 cases, while three electrodes were placed in one case due to venous anatomical limitations. Alternative venous routes were used when standard approaches were not feasible. No procedure-related complications occurred. The median electrode dwell time was 2 days.

A standardized planning and placement workflow enabled feasible EP-01 electrode placement without procedure-related complications in this consecutive series. Careful preprocedural assessment of patient-specific venous anatomy is essential and may necessitate alternative access strategies.